Adrenal function evaluation in critically ill dogs with low doses of synthetic ACTH / Avaliação da função adrenal em cães portadores de doenças críticas com baixa dose de ACTH sintético

The hypothalamus-pituitary-adrenal axis function may be impaired in patients with critical illnesses, especially cases of sepsis, named critical illness-related corticosteroid insufficiency (CIRCI). This study examined the function of the hypothalamic-pituitary-adrenal axis in normal dogs (n = 10) and dogs with critical diseases (n = 16), through determinations of endogenous ACTH (adrenocorticotropic hormone), basal cortisol and cortisol after stimulation in low doses of synthetic ACTH (1.0µg/kg/IV). The stimulation test with ACTH dose tested was verified as effective for evaluation of adrenal function in healthy and sick dogs. Ill dogs differed from healthy dogs by presenting higher basal cortisol values. Eight sick dogs presented a decrease in endogenous ACTH, basal cortisol, or Δ-cortisol. No significant differences were found between the control groups and critically ill dogs for the values of endogenous ACTH, cortisol after stimulation or Δ-cortisol. We concluded that the stimulation test with low-dose ACTH was effective for evaluation of adrenal function, as well as the fact that a considerable portion of critically ill dogs studied here, especially with sepsis, had evidence of inadequate corticosteroid response to stress.(AU)

A função do eixo hipotálamo-hipófise-adrenal pode estar comprometida em pacientes com doenças críticas, em especial casos de sepse, sendo nomeada de Insuficiência Corticosteroide Relacionada à Doença Crítica (ICRDC). O presente trabalho analisou a função do eixo hipotálamo-hipófise-adrenal em cães normais (n=10) e cães portadores de doenças críticas (n=16), por meio de determinações de ACTH (hormônio adrenocorticotrófico) endógeno, de cortisol basal e de cortisol após estímulo com baixa dose de ACTH sintético (1,0µg/kg/IV). Constatou-se que o teste de estimulação com ACTH na dose testada se mostrou eficaz para avaliação da função adrenal em cães sadios e doentes. Os cães doentes diferiram dos sadios ao apresentar valores maiores de cortisol basal. Oito cães doentes apresentaram diminuição do ACTH endógeno, do cortisol basal ou do Δ-cortisol. Não foram encontradas diferenças significativas entre os grupos Controle e Criticamente enfermos para os valores de ACTH endógeno, cortisol após estimulação ou Δ-cortisol. Concluiu-se que o teste de estimulação com baixa dose de ACTH mostrou-se eficaz para avaliação da função adrenal, assim como, uma parcela considerável da população de cães críticos aqui estudados, em especial com sepse, apresentaram evidências de resposta corticosteroide inadequada frente ao estresse.(AU)

Chromatographic analysis of lipid fractions in healthy dogs and dogs with obesity or hyperadrenocorticism.

Obesity and endogenous hyperadrenocorticism (HAC) are common clinical conditions in veterinary practice, and both conditions have clinical and laboratory similarities, such as weight gain and dyslipidemia. The objective of the present study was to characterize and compare the lipid profiles and plasma lipoprotein fractions in healthy dogs (n = 10), in obese dogs (n = 10), and in dogs with HAC (n = 6). All of the dogs were client owned. The lipoproteins were separated by fast protein liquid chromatography, and the plasma concentrations of total cholesterol and total triacylglycerol (TAG) were determined by enzymatic methods. When compared with the healthy and obese groups, dogs with HAC had a significant increase (P < 0.01) in the total concentrations of TAGs and cholesterol (CHOL), with higher distribution in the very low-density lipoprotein (VLDL)-CHOL fractions. In addition, the distributions of the high-density lipoprotein (HDL)-CHOL and HDL-TAG fractions were significantly lower (P < 0.01) in dogs with HAC than in healthy dogs. Considering the animals in this study, it was determined that the dogs with HAC differed significantly from the healthy and obese dogs regarding the metabolism of CHOL and TAG, as well as their VLDL and HDL fractions. Similar laboratory findings could allow veterinarians to distinguish obese dogs from those with HAC. In addition, dogs with HAC may be at higher risk for developing metabolic and atherosclerotic complications.